Heretofore, it has been accepted prior art practice to provide what was generally referred to as a fast idle cam which was positioned generally in accordance with the position of the choke valve of an associated carburetor. As is well known in the art, such choke valves were and are usually positioned in accordance with engine temperature. The cam, thusly positioned, coacts with a swingable abutment operatively connected to the engine throttle valve as to thereby be effective for holding the throttle valve open a greater degree during cold engine idle operation while permitting a lesser degree of throttle opening at engine idle once the engine has attained some preselected operating temperature.
Generally, in the past, such prior art arrangements have been found to be adequate. However, because of governmentally imposed standards, among other things, engines have steadily become smaller (of reduced displacement and power) while the consumer still continues to require such vehicular accessories as, for example, air conditioning units and the like which, when used, apply a disproportionate load on the smaller engine especially during idle engine operation. The extra load thusly placed on the engine, at idle operation, is often sufficient to stall the engine or, the very least, cause unacceptably rough engine operation. This, of course, applies to situations where normal engine operating temperature has been attained and therefore, there is no way in which the prior art fast idle cam (positioned by the choke valve) is able to assist the engine in compensating for the additional accessory load.
Further, it has been discovered that certain engines, upon vehicle deceleration, are to a significant degree driven by the vehicle to where exceptionally high magnitudes of intake manifold are created which, in turn, causes excessive fuel to be delivered into the engine induction passage means from the idle fuel metering system. This results in, among other things, increased fuel consumption, which coupled with a relatively small rate of air flow causes, in those vehicles so equipped, overheating of the exhaust catalytic converter.
The invention as herein disclosed and described is, among other things, directed to the solution of the foregoing and related and attendant problems of the prior art.